1. Technical Field
The present disclosure relates to a lighting device, and more particularly to a lighting device including a light guide plate.
2. Description of Related Art
Light emitting diodes are semiconductor elements. Light emitting diodes are often used as light emitting elements in indicating lights or display panels. In recent years, with the development of white light emitting diodes, a large number of light emitting diodes have been applied to lighting devices. When a lighting device utilizes a light emitting diode together with a light guide plate, the lighting device has the advantages of high efficiency, long life span, and a high degree of ruggedness compared to lighting devices using traditional fluorescent or incandescent bulbs.
Such a lighting device typically includes a light source, a bottom plate, a frame including a hollow region, a diffusion plate, and a reflective plate. Because the frame does not function to fix the light guide plate, the frame and the bottom plate needs to be assembled to position and fix the light guide plate. The light guide plate includes two light emitting surfaces respectively facing the hollow region of the frame and the bottom plate. Light emitted from the light emitting surface which is adjacent to the hollow region can be emitted through the hollow region, but light emitted from the light emitting surface which is adjacent to the bottom plate is shielded by the bottom plate. As a result, the reflective plate is often placed between the bottom plate and the light emitting surface adjacent to the bottom plate by manufacturers, such that the light emitted from the light emitting surface which is adjacent to the bottom plate can be emitted through the hollow region by the reflective plate, so as to increase the brightness of the lighting device. In addition, the diffusion plate can be located on the light emitting surface which is adjacent to the hollow region to increase the uniformity of the light.
However, such a conventional lighting device requires the bottom plate and the frame to position and fix the light guide plate, and as a result of this configuration, the material and assembly costs are increased. Furthermore, since the conventional lighting device includes the bottom plate, the lighting device only can emit light through a single side, such that light output utility is reduced and electric power is wasted.